1. Field of the Invention
The invention relates to a sensor for liquid and/or gas analysis, which is connected to a measuring and/or evaluating system or, respectively, to a higher ranking control system and which has a sensor housing.
2. Description of Related Art
Sensors of the type described above are known in different forms from the prior art. A liquid sensor having a sensor housing is thus known from PCT Patent Application Publication WO 2005/031339 and corresponding U.S. Pat. No. 7,587,953 that is connected in a contact-free manner via a coupling to a transducer and further to a measuring and/or evaluating system. A receiving sensor for collecting measured values, a pre-processing unit for pre-processing the collected values, an analog-digital converter for converting the collected analog measured values into digital measured values and means (modem, power supply unit, inductor or radio module) for contact-free transmission of the digital measured values to the transducer are located in the sensor housing. The coupling has means (inductor or radio module, amplifier, modem) for receiving the contact-free transmitted digital measured values and an interface for transmitting the measured values to the transducer. The contact-free transmission of the measured values between the sensor and the coupling serves, in particular, the galvanic de-coupling of the sensor from the measuring and/or evaluating system.
Liquid and/or gas sensors have a relatively short operating life and thus have to be regularly exchanged. For economic reasons, it has been attempted in previous years to relocate as much of the electronics as possible from the sensor into the coupling. For this reason, the transmitter part of the transducer is arranged in the coupling or is implemented there, for example, by means of a processor or a computer program running on the processor in the known liquid and/or gas sensors. For economic reasons, the electronics are thus split into sensor electronics, on the one hand, and cable-connection electronics, on the other hand, in which essentially the sensor signals are converted into a proprietary protocol in order to be able to then transmit them to the measuring and/or evaluating system. The interface between the liquid and/or gas sensor and the cable (for example, via a coupling for contact-free signal transmission) is costly and causes technical problems in respect to ambient conditions.